Effects of the pore shape polydispersity on the percolation threshold and diffusivity of porous composites: Theoretical and numerical studies

Understanding the effects of the pore shape polydispersity on the percolation and diffusivity of the porous network has a great impact on the assessment and optimization of the composites' durability. In this work, a comprehensive framework is developed to study the effects of the pores' shape polydispersity on composites' diffusivity. In the present framework, the quantitative relationship between pores' shape polydispersity and percolation threshold of porous networks are established by an average excluded area formula (AEAF). Combining AEAF with the generalized effective medium theory (GEMT), the diffusivity of porous composites comprising polydisperse-shaped pores are predicted. To obtain the excluded area of polydisperse-shaped superoval particles, a new algorithm is proposed to detect whether the inter-superoval contact or not. Furthermore, a finite difference method (FDM) is employed to numerically calculate the diffusivity of the composites. Finally, the reliability of GEMT-AEAF theoretical framework is validated by comparing with numerical results from FDM. (c) 2021 Elsevier B.V. All rights reserved.